Due to increased levels of toxicity caused by chemicals found within the water supply, water filtration has become widespread within many homes. Point-of-use (POU) water treatment devices are designed to treat drinking water for use in the home. These devices can be attached to a faucet and/or installed under a sink. They differ from point-of-entry (POE) devices, which are installed on the water line as it enters the home and treats all the water in the building.
Many households today have reverse-osmosis (RO) units installed. These devices use a membrane that screens out chemicals, such as chloride and sulfate as well as most other contaminates found in the water supply. RO systems are generally multi-stage systems and include an activated charcoal filter since RO does not remove volatile organic compounds. A RO system can remove particles down to 1 Angstrom. However POU RO systems can waste a substantial amount of water for every gallon that is treated. This is because RO purification at normal water pressure is roughly twenty percent efficient. Accordingly, there is a need for a POU RO system that provides filtered water while minimizing waste water.